Method and apparatus for using nanogalvanic alloys to produce hydrogen

The invention described herein may be manufactured, used and licensed by or for the U.S. Government.

Embodiments of the present invention generally relate to nanogalvanic alloys and, more specifically, to a method and apparatus for producing hydrogen using nanogalvanic alloys.

Nanogalvanic alloys, especially aluminum-based nanogalvanic alloys, are characterized by their galvanic microstructure, which comprises an anodic matrix consisting of aluminum, an aluminum alloy, and a cathodic dispersed phase of another metal composition. These other metals may comprise, for example, but not limited to, tin, magnesium, silicon, bismuth, lead, gallium, indium, zinc, carbon, or a mixture of these metals. These alloys produce hydrogen gas when the cathodic disperse phase forms galvanic couples with the anodic matrix and the resulting galvanic metal microstructure comes in contact with water or any liquid containing water (aqueous solution). The nanostructured galvanic couple, with aluminum as the anode and the other metal element as the cathode, rapidly disturbs the formation of the native oxide layer and continually exposes fresh aluminum surfaces to hydrolysis.

The hydrogen produced by combining nanogalvanic alloys with liquid water may be coupled to a fuel cell to form a power supply to produce electrical energy. However, producing hydrogen from a combination of a nanogalvanic alloy and liquid water requires water to be readily available and, for portable systems, requires the water to be carried. As such, utilizing such a portable power supply requires carrying the weight of liquid water which limits the applications of such a power supply.

Therefore, there is a need in the art for a method and apparatus for using nanogalvanic alloys to produce hydrogen without using liquid water or liquids containing water.

Embodiments of the present invention include a method and apparatus for using nanogalvanic alloys to produce hydrogen without using liquid water or liquids containing water in accordance with the following description and drawings.

Embodiments of the present invention include a method and apparatus using nanogalvanic alloys to produce hydrogen using water vapor. In one embodiment, a nanogalvanic alloy is exposed to water vapor having a humidity level high enough to cause a galvanic reaction between the water vapor and the alloy to produce hydrogen. The water vapor may be available from atmospheric conditions or may be engineered water vapor.

The production of aluminum-based nanogalvanic alloys for use in generating hydrogen is described in commonly assigned US patent publication number 2020/0024689, filed 23 Jul. 2018, entitled “Aluminum Based Nanogalvanic Compositions Useful for Generating Hydrogen Gas and Low Temperature Processing Thereof,” (referred to herein as the '689 patent publication) which is hereby incorporated herein by reference in its entirety. The '689 patent publication describes alloys comprised of a refined microstructure, ultrafine or nano scaled, that when reacted with water or any liquid containing water will spontaneously and rapidly produce hydrogen gas at ambient or elevated temperature. These metals, termed here as aluminum based nanogalvanic alloys have applications that include, but are not limited to, energy generation on demand. The alloys may be composed of primarily aluminum and other metals, e.g., tin bismuth, indium, gallium, lead, etc. and/or carbon, and mixtures and alloys thereof. The alloys may be processed by ball milling for the purpose of synthesizing powder feed stocks, in which each powder particle will have the above-mentioned characteristics. These powders can be used in their inherent form or consolidated using commercially available techniques for the purpose of manufacturing useful functional components as well as cylindrical or rectangular bars.

Embodiments of the present invention pertain to the utilization of nanogalvanic aluminum based alloys in powder or consolidated form for spontaneous, facile generation of hydrogen, by reacting the alloy with natural or engineered atmospheric humidity. Atmospheric humidity is a measure of the amount of water vapor or moisture in the air. This includes heated steam, i.e., the vapor into which water is converted when heated, forming a white mist of minute water droplets in the air or undercooled vapor such as fog, mist, haze, i.e., a visible mass of condensed water vapor suspended in the atmosphere which may or may not be heated, or some mixture of water vapor with another chemically distinct form of vapor or other phase. Engineered atmospheric humidity specifies the use of, but not limited to: mechanical, thermal, acoustic, ultrasonic, photonics, electromagnetic radiation, radiation and magnetic energy to form suspended water vapor. Suspended refers to being airborne for some undefined amount of time.

In an exemplary embodiment described with reference tobelow, engineered water vapor is created using a commercially available ultrasonic vaporizer to supply a sustained water vapor to a nanogalvanic alloy for continuous and controlled hydrogen production for use with a permeable electron membrane (PEM) fuel cell or similar device. As such, a light-weight, compact electrical power supply is created.

depicts a schematic diagram of energy producing apparatusthat uses nanogalvanic alloys to produce hydrogen gas from water vapor in accordance with an embodiment of the present invention. The apparatuscomprises a hydrogen gas producing assemblyand power generator. The hydrogen gas producing assemblycomprises a water vapor sourceand a reaction assembly.

In one exemplary embodiment, the water vapor sourcecomprises a water or aqueous solution source, e.g., conduit (water pipe), bottle, bladder, etc. for supplying water or other aqueous solutionto a vapor producing device. The vapor producing devicemay utilize, but is not limited to, mechanical, thermal, acoustic, ultrasonic, photonics, electromagnetic radiation, radiation and magnetic energy to form suspended water vapor.depicts the use of, for example, an ultrasonic vaporizercomprising a piezoelectric transducer (not shown) that vibrates at about 1-2 MHz to vaporize waterthat contacts the transducer. A controllerapplies power to the deviceto control activation. The controllermay modulate activation of the deviceto ensure a specific water vapor pressure is maintained as the alloy is hydrolyzed by the reaction, e.g., less than 45 psi. In other embodiments, other devicesmay be used to generate water vaporwithin the reaction assembly.

In other embodiments, the water vapor source may be atmospheric water vapor, i.e., humid air, that is channeled into the reaction assembly. In one embodiment, humidity of the atmospheric water vapor need only be 60% or more to contain sufficient water vapor to create and maintain a hydrolysis reaction with nanogalvanic alloy to produce hydrogen.

The reaction assemblycomprises a reaction chamber, hydrogen gas conduitsand, and a desiccant chambercontaining a desiccant. In one embodiment, the reaction chambercontains at least one barof aluminum-based nanogalvanic alloy. The manufacture of which is described in detail in the '689 patent publication. In one embodiment, the bar contains nanogalvanic aluminum 5056 and 3% bismuth powder that is pressed into a cylinder-shaped bar. In other embodiments, the bar may be formed in other shapes, e.g., rectangular, square, star, octagon, etc.) or the alloy may be placed in the chamberin powder form. Within the chamber, the baris exposed to water vaporto produce hydrogen to achieve a pressure at the couplerof, for example, about 7 psi. In one embodiment, the baris positioned with its long axis in the vertical direction. This orientation allows the hydrolyzed alloy to drop from the bar's surface and expose “fresh” alloy beneath the surface. In some embodiments, a plurality of bars are arranged in the chamber. In other embodiments, a plurality of chambers, each containing at least one bar, may be arranged in an array.

Hydrogen gas produced by the reaction exits the chamberthrough coupling(i.e., a gas conduit) and passes through a desiccant chamberto remove water from the hydrogen gas. The desiccant chambercomprises a desiccantfor removing water from a gas. In one embodiment, the desiccantis a block, bar, or sheet of aluminum based nanogalvanic alloy. By using the alloy as a desiccant, water is removed from the hydrogen gas and additional hydrogen is released into the chamber. In other embodiments, other desiccants may be used such as, but not limited to, silica gels, molecular sieve, sorbent and the like. The dried hydrogen gas flows from the chamberthrough coupling(i.e., a gas conduit) to a power generator, such as a PEM fuel cell. The hydrogen producing assemblyproduces, for example, a continuous 7 psi flow of hydrogen gas into the fuel cell. As such, the fuel cell produces electricity at terminals. In one embodiment, with a 7 psi source of hydrogen, the fuel cell may produce approximately 10 Watts of DC power at a nominal 6 volts. In other embodiments, the power generatormay be any form of power conversion device including, but not limited to, an internal combustion engine adapted to combust hydrogen. In other embodiments, the hydrogen gas may be coupled from the conduitand stored in a hydrogen gas storage device (not shown), e.g., gas bottle, tank or solid-state hydrogen storage system (metal hydride).

depicts a flow diagram of a methodof operation for the apparatus ofin accordance with an embodiment of the present invention. The methodbegins atand proceeds towhere the method generates water vapor within the reaction chamber. As described above, the water vapor may be generated by many types of devices or using atmospheric water vapor that is channeled into the reaction chamber.

At, the water vapor reacts with the bar of nanogalvanic alloy to produce hydrogen gas. At, the water vapor is removed from the hydrogen gas by passing the hydrogen gas through a desiccant material. In one embodiment, the desiccant is a bar, block, sheet, etc. of aluminum based nanogalvanic alloy which operates to remove water vapor as well as produce additional hydrogen gas. In other embodiments, other desiccants may be used such as, but not limited to, silica gels, molecular sieve, sorbent. The methodends at. The hydrogen gas produced using methodmay be used for industrial purposes, e.g., stored, or may be used for fuel by coupling the gas to a fuel cell or other energy conversion device, e.g., internal combustion engine.

Here multiple examples have been given to illustrate various features and are not intended to be so limiting. Any one or more of the features may not be limited to the particular examples presented herein, regardless of any order, combination, or connections described. In fact, it should be understood that any combination of the features and/or elements described by way of example above are contemplated, including any variation or modification which is not enumerated, but capable of achieving the same. Unless otherwise stated, any one or more of the features may be combined in any order.

As above, figures are presented herein for illustrative purposes and are not meant to impose any structural limitations, unless otherwise specified. Various modifications to any of the structures shown in the figures are contemplated to be within the scope of the invention presented herein. The invention is not intended to be limited to any scope of claim language.

Where “coupling” or “connection” is used, unless otherwise specified, no limitation is implied that the coupling or connection be restricted to a physical coupling or connection and, instead, should be read to include communicative couplings.

Where conditional language is used, including, but not limited to, “can,” “could,” “may” or “might,” it should be understood that the associated features or elements are not required. As such, where conditional language is used, the elements and/or features should be understood as being optionally present in at least some examples, and not necessarily conditioned upon anything, unless otherwise specified.

Where lists are enumerated in the alternative or conjunctive (e.g., one or more of A, B, and/or C), unless stated otherwise, it is understood to include one or more of each element, including any one or more combinations of any number of the enumerated elements (e.g., A, AB, AC, ABC, ABB, etc.). When “and/or” is used, it should be understood that the elements may be joined in the alternative or conjunctive.

While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.